The new Ecobee4 smart thermostat has Alexa built right in, but the previous generation Ecobee3 is still great, and Amazon’s clearing them out for an all-time low $170 right now. That’s about the same price as an Ecobee Lite, but you get an all-important remote temperature sensor, plus the ability to control HVAC accessories like humidifiers, dehumidifiers, and ventilators.